HUT61518A - Process for refining liquid, raw aldehyde mixture product - Google Patents

Abstract

A method for distilling a crude aldehyde product mixture of branched chain and straight chain aldehyde in a single distillation column to concurrently obtain three separate product streams, i.e. a purified branched chain aldehyde stream and two different purified straight chain aldehyde streams.

Description

The present invention relates to a process for refining a liquid crude aldehyde fly product, whereby both branched and straight chain aldehyde are obtained simultaneously and separately. More particularly, the present invention relates to a branch and a straight line

Distillation of a crude aldehyde mixture product containing a mixture of 73641-2450 / VO chain aldehydes in a single distillation column to give simultaneously three separate product streams, one containing purified branched aldehyde and the other two containing two purified straight chain aldehydes .

Methods for preparing aldehydes based on the reaction of an olefinically unsaturated compound with carbon monoxide and hydrogen (more commonly referred to as synthesis gas) in the presence of a rhodium-phosphorus complex catalyst and a free phosphorus ligand are well known in the art. Examples include the low-pressure oxohydroformylation process described in U.S. Patent 3,527,809, and the rhodium catalyst, gas and liquid catalysts disclosed in U.S. Patent Nos. 4,148,830, 4,247,486, and 4,593,127. circulating hydroformylation processes. The resulting aldehyde products are a mixture of normal (linear) and isomeric (branched) aldehydes corresponding to the starting material of the olefin, formed by the addition of a formyl group (-CHO) to a carbon atom of an ethylene group (e.g. -CH = CH 2) of the olefin. Hydroformylation of propylene yields, for example, n-butyraldehyde (CH3CH2CH2CHO) and isobutyraldehyde [CH3CH (CHO) CH3]. Such hydroformylation processes are generally designed to yield aldehyde products rich in the normal (straight-chain) isomer.

Apart from the above, such continuous hydroformylation ···· · · ····· · * * · · · · · · · ·

3 processes, as taught in U.S. Patent Nos. 4,148,830 and 4,247,486, inevitably result in high-boiling liquid aldehyde condensation by-products such as dimers, trimers and tetramers as solvents for the hydroformylation process and other heavy liquid fractions. Therefore, these high boiling components are always present in the crude aldehyde compound product in small amounts, even if the resulting aldehyde product is separated from its light components (such as carbon monoxide, hydrogen, unreacted alkylene, alkane by-products and the like) by continuous gas circulation. hydroformylation process, or if the initial aldehyde product is separated from its light components and the solution containing the catalyst, as in a continuous fluid circulation hydroformylation process. Even if the lower boiling branched aldehyde is actually separated from the higher boiling straight chain modification, to purify the higher aldehyde of the branched aldehyde (thus isobutyraldehyde) (such as n-butyraldehyde), contains an organic heavy fraction which would be desirable for its use.

As a result, prior art two-stage distillation processes using two separate distillation columns have become conventional for refining a crude aldehyde mixture product and separating the branched aldehyde product from the straight chain aldehyde product.

- 4 produced by a conventional continuous rhodium-catalyzed hydroformylation process. For example, a purified branched aldehyde (such as isobutyraldehyde) is first separated from the crude aldehyde mixture product in a first distillation column, and then the remaining normal (straight chain) aldehyde (such as n-butyraldehyde) is further refined or purified from further residual higher boiling by-products. by a second distillation in a second distillation column.

However, the industrial refining of the crude aldehyde mixture product by such a double distillation process has two major disadvantages. The first disadvantage is the very high energy cost of such industrial-scale double distillation processes. The second disadvantage is the significant loss of aldehyde due to the high-boiling products resulting from in situ conversion in such distillation processes due to the use of high temperatures to obtain as many straight-chain aldehydes from the high-boiling products as possible. Studies have shown that loss of at least 1-2 wt.% Of straight chain aldehyde is caused by in situ conversion to high boiling products and is significant for any industrial operation such as the hydroformylation operations discussed above with a few million kg aldehyde capacity per year.

For more than a year prior to the invention, experiments have been conducted in one of the Applicant's plants in the United States using a single distillation column, which purifies the invention. · Yielded branched-chain isobutyraldehyde at the top of the distillation column and substantially all of the straight-chain n-butyraldehyde was collected as distilled gas in the lower side opening of the same distillation column. However, as with the traditional two-stage distillation process using two distillation columns, to obtain substantially all of the n-butyraldehyde at the side junction of a single distillation column, substantially the same distillation temperature (115-140 ° C) is required as for the n-butyraldehyde from a boiling point organic product in a second distillation column by conventional distillation, which results in substantially the same aldehyde loss due to the in situ formation of high boiling products as it normally does in the second distillation column.

It has been found that it is not necessary to use such high distillation temperatures to separate and recover both the purified branched aldehyde and the purified straight chain aldehyde from a crude aldehyde mixture product using a single distillation column. As a result, the disadvantages associated with conventional distillation refining of crude aldehyde mixture products can be avoided, or at least greatly minimized, by the process of the present invention, which will be described in detail below.

Accordingly, it is an object of the present invention to provide a novel process for refining a crude aldehyde mixture containing a branched and straight chain aldehyde, wherein the crude aldehyde product is purified by simultaneous separation of purified aldehyde and purified straight chain aldehyde in a single distillation column. .

Accordingly, the present invention provides a process for refining a liquid crude aldehyde mixture product, wherein the crude product comprises 95-99.95% by weight of straight and / or branched aldehydes having from 4 to 5 carbon atoms, based on the total weight of the product. In the process of the present invention, the liquid crude aldehyde compound starting material is introduced into a distillation column 10 and the normal boiling point of the straight chain aldehyde in the starting material is obtained.

Distillation is carried out at a bottom temperature above 1-35 [deg.] C., at the same time

(i) a stream of liquid aldehyde consisting essentially of purified branched aldehyde taken at or near the top of the distillation column, (ii) up to 70% by weight of straight chain aldehyde in the starting material and 33% by weight of organic heavy fractions in the starting material containing less than a fraction of the evaporated aldehyde product stream and residues

4) iii) Purified liquid aldehyde obtained at or near the bottom of distillation column 10 and containing less than 1% by weight of aldehyde in the organic fraction and at least 67% by weight of the heavy fraction in the starting material.

The figure shows a schematic flow diagram of an apparatus for carrying out the process according to the invention, comprising: a distillation column 10 for distillation of a crude aldehyde mixture product fed through line 2 to simultaneously purify a branched line 8 on or near the top of column 10. chain aldehyde, a straight stream aldehyde purified by steam 12 through a line 12 to the side of the column 10 and a second purified aldehyde product exiting via a line 14 at or near the bottom of the column 10.

The crude aldehyde mixture product used herein can be prepared by any metal (preferably rhodium complex) catalyzed hydroformylation in the presence of any conventional free organic phosphorus ligand. Such oxo processes and their relationships are well known in the art, such as those described in U.S. Patent 4,148,830. U.S. Patent Nos. 4,247,486 and 4,593,127, and U.S. Patent Application Serial No. 370,806, filed June 23, 1989, illustrate the continuous fluid and gas circulation processes, the entire contents of which are incorporated herein by reference. comprising the preparation of aldehydes rich in straight chain n-isomers by reaction of an olefinic compound with hydrogen and carbon monoxide in a liquid reaction medium which, in addition to the aldehyde product, soluble rhodium (organic) phosphorus complex catalyst, free organic phosphorus ligand s contain high boiling aldehyde condensation by-products.

It will be appreciated that the particular manner in which the hydroformylation reaction is carried out and the specific reaction conditions used for the hydroformylation are not critical to the invention and can be varied and adapted within wide limits to meet individual needs and to produce the desired specific aldehyde product.

Accordingly, it may contain 3 or 4 carbon atoms in the olefin starting material of the hydroformylation process which can provide the starting materials of the process of the invention as a crude aldehyde mixture. Such olefins include propylene, 1-butene, (cis or trans) 2-butene and

2-methylpropene (isobutylene). Of course, if desired, a mixture of different olefins can be used as starting material. For example, the starting material is sometimes conventional

A mixture of 1-butene and 2-butene is used. The most preferred olefin is propylene.

Similarly, any conventional rhodium-phosphorus complex catalyst can be used and such catalysts and their preparation methods are known in the art. These rhodium-phosphorus complex catalysts may include any rhodium (organic) phosphorus complex, such as the rhodium (organic) phosphine or rhodium (organic) phosphite complex hydroformylation catalysts used hitherto in such hydroformylation processes. Of course, if desired, a mixture of these catalysts can be used. It will further be appreciated that the amount of complex catalyst present in the reaction medium of a particular process should be limited to the minimum required to provide the desired rhodium concentration to be used and which is the basis for the minimum amount of catalytic amount of rhodium metal required to catalyze the desired hydroformylation process. The rhodium concentration is generally 10-1000 ppm as the free metal, which is suitable for most hydroformylation processes. Preferably from 10 to 700 ppm, more preferably from 25 to 500 ppm, of rhodium, calculated as the free metal.

Accordingly, the hydroformylation process of the present invention is carried out in the presence of a free phosphorus ligand, i.e., a ligand that does not complex with the rhodium complex catalyst. Although preferably the free phosphorus ligand is the same as the phosphorus ligand of the rhodium-phosphorus complex catalyst, this is not necessary and different ligands may be used in a particular process if desired. Accordingly, like the rhodium (organic) phosphorus complex catalyst, any conventional organic phosphorus ligand known in the art can be used as the free ligand for the preparation of the ligands. These free phosphorus ligands may include any organic phosphine or organic phosphite ligand used to date in such hydroformylation processes. Of course, mixtures of such ligands may also be used if desired. Thus, the hydroformylation process can be carried out in the presence of any excess of free phosphorus ligands, for example if at least 1 mole of free phosphorus ligand is present in the reaction mixture, based on 1 mol of rhodium metal. The amount of free phosphorus ligand employed will generally depend only on the desired aldehyde product, the olefin used and the complex catalyst used. Accordingly, it is most suitable if the amount of free phosphorus ligand present in the reaction medium is based on 1 mol of rhodium present.

2-300 moles. Generally, large amounts of free triarylphosphine ligands, such as triphenylphosphine, such as triphenylphosphine, are used to obtain adequate catalytic activity and / or catalyst stability, such as triphenylphosphine, and other organic phosphorus compounds. ligands such as alkylarylphosphines and cycloalkylarylphosphines and / or organic phosphites provide acceptable catalyst stability and reactivity without unnecessarily reducing the conversion rate of certain olefins to aldehydes if the free ligand in the reaction medium is 1 mole of rhodium It is present in an amount of -100, more preferably 15-60 mol. Rhodium-phosphorus complex catalysts and free phosphorus ligands are further illustrated in 3,527

809, 4 148 830, 4 247 486, 4 283 562, 4 400 548, 4 482 749, 4 496,768 , 4 599,206 , 4 668,651 , 4 716,250 , 4 717,775 , 4 731 486, 4 737 588, 4 748 261, 4 769 948, 4 744 361, 4 885 401; 4

U.S. Patent Nos. 496,748; and International Publication No. WO 80/01690, published August 21, 1980. More preferred ligands and complex catalysts include triphenylphosphine ligand described in U.S. Patent Nos. 3,527,809, 4,148,830 and 4,247,486 and the rhodium triphenylphosphine complex catalyst; alkylphenylphosphine and cycloalkylphenylphosphine ligands and rhodium-alkylphenylphosphine and rhodium-cycloalkylphenylphosphine complex catalysts described in U.S. Pat. No. 4,283,562; Organophosphite ligands and rhodium (organic) phosphite complex catalysts described in U.S. Patent Nos. 4,737,588, 4,717,775, 4,774,361, 4,668,651, and 4,748,261. The most preferred ligand is triphenylphosphine (TPP), while the most preferred catalyst is a rhodium-TPP complex.

As previously described, the hydroformylation reaction is carried out in the presence of high-boiling aldehyde condensation by-products. The continuous hydroformylation reactions used herein naturally involve in situ formation of such higher boiling aldehyde by-products (such as dimers, trimers, and tetramers) during the hydroformylation process, as described in detail in U.S. Patent Nos. 4,148,830; 4,247,486; 4,593,127; and U.S. Patent Application No. 370,806 filed June 23, 1989. Such aldehyde by-products provide an excellent carrier for the fluid-circulation processes employing the catalyst. When starting the continuous process, virtually any suitable solvent may be used if desired (aldehyde compounds corresponding to the desired aldehyde products are preferred), and the nature of such continuous processes will generally include both aldehyde products and higher boiling aldehyde condensation by-products. Of course, if desired and properly applied, the effect of the aldehyde condensation by-products can be exploited. It will also be appreciated that the amount of such high-boiling aldehyde by-products in the reaction medium will vary widely and will generally be determined solely by the factors of the equipment and the characteristics of the aldehyde product to be produced. The hydroformylation reaction may be initiated, for example, in the absence of aldehyde condensation by-products or in the presence of small amounts of higher-boiling aldehyde condensation by-products acting as solvents for the rhodium complex catalyst, but may be more than 70% or 90% by weight of the total liquid reaction medium. in excess of

- 13 even in the presence of such condensation by-products. For most purposes, the weight ratio of the aldehyde to the higher boiling point aldehyde condensation by-products is generally suitable from 1: 4 to 20: 1. Likewise, it is understood that other conventional organic co-solvents may be present if desired.

While the conditions for the hydroformylation reaction, as discussed above, can vary widely, the process is generally carried out in such a way that the total pressure of the gas mixture of hydrogen, carbon monoxide, and unsaturated starting material containing an olefinic bond is less than

10.4 MPa, preferably 3.12 MPa, and more preferably 2.43 MPa. The minimum value of the total pressure of the reaction partners is not particularly critical and is mainly limited by the amount of reaction partners required to achieve the desired reaction rate. In detail, in the hydroformylation process of the invention, the partial pressure of carbon monoxide is preferably between 6.9 kPa and 832 kPa, more preferably between 20.8 kPa and 624 kPa, while the partial pressure of hydrogen is preferably 69.4 kPa and

1.11 MPa, and more preferably between 104 kPa and 694 kPa. The gaseous hydrogen has a molar ratio of H2: CO to carbon monoxide of from about 1:10 to about 100: 1, more preferably the hydrogen to carbon monoxide has a molar ratio of from 1: 1 to 50: 1.

As mentioned above, the hydroformylation process can be carried out at a reaction temperature of 50 to 145 ° C.

• · • · · · · · · · · · ·

The reaction temperature for hydroformylation is generally from 60 to 120 ° C, more preferably from 75 to 115 ° C.

The crude aldehyde mixture products used as starting materials for the process of the present invention may contain substantially aldehydes, high-boiling organic materials and, optionally, free organic phosphorus ligands used in the hydroformylation process; In the case of a continuous gas-circulation hydroformylation process, the starting material is preferably obtained by separating the starting aldehyde product from the light components (such as compounds having a lower boiling point than the compounds of the aldehyde product) or by preferentially obtaining the starting material. the initial aldehyde product is separated from the light components and the solution containing the catalyst.

Thus, the aldehydes in the crude aldehyde mixture product of the present invention are dependent on the olefinic starting material of the hydroformylation process from which the product is derived and may therefore contain 4 or 5 carbon atoms from propylene or butylene. In addition, it is obvious that such aldehydes are formed as a mixture of (straight chain) normal and (branched) iso-aldehydes. Examples of such aldehyde products include 4-carbon aldehydes such as mixtures of n-butyraldehyde (n-butanal) and iso15 butyraldehyde (isobutanal) and 5-carbon aldehydes such as n-valeraldehyde (n-pentanal) and el. chain pentanal isomers, i.e. 2-methylbutyraldehyde,

Mixtures of 3-methylbutyraldehyde and / or pivaldehyde. The molar ratio of normal to branched aldehyde isomers in said aldehyde mixtures may be from 1: 1 to 50: 1, or even higher, the upper limit of the normal aldehyde content being dependent only on the hydroformylation process to give the crude aldehyde product starting material. .

Similarly, organic heavy fractions in the crude aldehyde mixture product useful in the process of the invention include any organic solvent and organic by-product boiling above the boiling point of the straight-chain aldehyde product of the hydroformylation process from which the aldehyde mixture product is derived; these may be liquid aldehyde condensation by-products (dimers, trimers, tetramers, and the like) as discussed above, for example, in U.S. Patent No. 4,148,830, and other conventional higher-boiling by-products such as the corresponding alkanols. It is understood that such crude aldehyde compound products may also contain small amounts of residual light fractions (such as unreacted olefin and alkane by-products) and organic phosphorus compound impurities such as free (organic) phosphorus ligand and / or its corresponding oxide and alkyl substituted phosphorus compounds which as a result of their formation or release • · ···· ·· <

• · · · · · · · · · ·

16 are present in the hydroformylation process.

The crude aldehyde compound products useful in the process of the present invention may be derived, for example, from the gas circulation hydroformylation process described in the patents cited above and in U.S. Patent No. 4,247,486; Indications, Winter 1982/83, International Journal of Davy McKee, 1 and 20-28. pages, Davy Corporation, London, England]. Similarly, the crude aldehyde mixture product for use in the process of the present invention may be derived from a liquid catalyst circulation process described in the patents cited above and preferably described, for example, in the primary reactor system of Figure 1 of U.S. Patent 4,593,127. U.S. Patent No. 1,202,326; U.S. Patent Application No. 370,806, filed June 23, 1989; and U.S. Patent Application Serial No. 07-611,081, filed September 9, 1990, to the Applicant; U.S. Patent No. 4,198, which relates to a new process for separating light fractions from an aldehyde mixture product. Hereby we refer to the entire content of the above announcements. Preferred liquid crude aldehyde mixture products useful in the process of the present invention are derived from liquid catalyst circulation hydroformylation processes. In addition, according to the state of the art and similar to gas circulation processes, it is advantageous for the liquid catalyst circulation process to be an aldehyde mixture.

At least the majority of the light fraction is removed from its product 17 before separation of the branched aldehyde isomer from the higher boiling straight chain aldehyde. However, regardless of the type of purification process that may be used to remove the light fraction and / or organic phosphorus impurities from the crude aldehyde mixture product obtained in the liquid catalyst circulation process, the crude aldehyde mixture product is preferably passed through a stabilizer. as shown in column 7 of the figure on page 23 of the above article in Indications before using the crude aldehyde mixture product as a liquid starting material for the process of the invention.

The crude aldehyde mixture product useful in the process of the invention may therefore contain from about 95% to about 99.95% by weight, preferably from 97% to 99.95% by weight, of aldehyde; the remainder of the liquid aldehyde mixture product consists essentially of heavy organic fractions.

In accordance with the accompanying drawing, which schematically illustrates the invention, the refining process of the present invention may be carried out in any suitable distillation column provided with two side openings for draining the liquid and vapor streams of the aldehyde product. The distillation column therefore includes any distillation or packed column or other suitable evaporation apparatus 10 in which distillation can be performed (Chemical Engineering Handbook, Perry and Chilton, 5th Edition, pp. 13-3).

• ·

page 13-1. 13-19. pages 13-18. 13-50. page, Unit Operations in Chemical Engineering, McCabe and Smith,

3rd Edition, page 548]. The type of tray or tray in the column is not critical to the invention and any type of tray or tray can be used. In addition, the number of trays or separation sections used is not critical, but should be sufficient to achieve the desired separation. The liquid crude aldehyde mixture product starting material is introduced into the distillation column 10 in the usual manner for near-boiling isomers such as n-butyraldehyde and isobutyraldehyde, e.g. at the top and bottom of column 10, preferably at the middle of the column (line 2). . The exact location of the introduction of the aldehyde mixture product starting material is also not critical to the invention and is preferably determined by standard engineering practice.

The liquid crude aldehyde product starting material is then distilled to remove simultaneously purified purified branched iso-aldehyde and purified straight-chain normal aldehyde and light fractions from the starting material. Evaporated light fractions (i.e., lower boiling points of the branched aldehyde, such as unreacted olefin, alkane, and the like) are discharged, for example, into the upper part of the apparatus (through conduit 4) and then cooled (in condenser 15) and according to the invention, condensed partially or completely. Non-condensable materials are blown (via line 6), condensable materials such as water are recovered, or blown (through line 3). In addition, if desired, a portion of the condensed overhead product (via line 7) may be returned to the column 10 as a reflux.

The purified branched chain iso-aldehyde (which is lighter, i.e., lower in boiling point than the straight chain normal aldehyde) may be conducted at or near the top of the distillation column. The branched iso-aldehyde is preferably discharged as a liquid side stream (via line 8) to the feedstock feed of the liquid crude aldehyde mixture. point slightly higher. The exact location of this is not critical, and the preferred location can be determined by standard engineering practice.

Simultaneously, purified, straight-chain normal aldehyde in vapor state (via line 12) is conducted as a vapor stream on the side of the apparatus below the feed point of the liquid crude aldehyde product starting material. The exact location of the removal is not critical in this case, and the advantageous location of the removal can be determined by standard engineering practice. If desired, a droplet separator (not shown) may be used to return the liquid entrapped by the evaporated stream of straight chain aldehyde to the column 10, but such a droplet separator is not required or essential for the process of the present invention.

The remaining purified liquid aldehyde is recovered at or near the bottom of column 10 (line 14). If desired, a portion of the straight chain aldehyde leaving the bottom of column 10 may be heated in a boiler 20 and returned to column 10. The liquid aldehyde bottom product consists essentially of straight-chain aldehyde and the amount of purified heavy organic fractions contained in the purified liquid aldehyde is less than 1% of the total weight of aldehyde fed to the distillation column 10 and at least the heavy crude aldehyde wt%.

In the refining process of the present invention, distillation of the liquid crude aldehyde mixture product starting material can be carried out under the following conditions:

The bottom temperature of the distillation column 10 is 1-35 ° C, preferably 10-35 ° C, above the normal boiling point of the straight aldehyde of the liquid crude aldehyde compound starting material (i.e. 101.4 kPa) and The head pressure of the 10 distillation columns is between 6.94 kPa and 207 kPa, preferably between 6.94 kPa and 103.5 kPa. In the upper part of the distillation zone, where the evaporated light fractions and the branched aldehyde are removed, the operating conditions (such as temperature, pressure, reflux ratio and the like) are not too critical and primarily depend only on the practical operating conditions which remove the fractions. necessary to achieve the desired result and to ensure that the aldehyde effluent stream contains at least 99% by weight of branched aldehyde and does not exceed 1% by weight of the heavy organic fractions of the liquid crude aldehyde product starting material. In addition, the amount of the liquid branched aldehyde thus obtained is preferably substantially the same as the amount of branched aldehyde in the crude liquid aldehyde mixture starting material. It will be understood that the heat required to distil the aldehyde compounds can be provided by any conventional heat exchanger. It is also to be understood that while the best conditions for achieving the best results and desired efficacy for the process of the invention will depend upon the practice of using the process of the invention, only a certain amount of experimentation is required to provide conditions that are optimal belong to the specialist. Necessary knowledge will be readily obtained by following the preferred embodiments of the invention described herein and / or by simple, routine experimentation. Higher distillation pressures, for example, generally require higher temperatures and lower pressures require lower temperatures.

Preferably, the process of the invention controls the temperature and pressure conditions at the bottom of the apparatus so that the amount of purified, evaporated straight chain aldehyde in the stream flowing to the side of the apparatus is generally not greater than the amount of straight chain aldehyde in the liquid crude aldehyde product. 70%, wherein the purified, evaporated straight chain aldehyde contains less than 33% by weight of the organic heavy fractions in the liquid crude aldehyde mixture starting material. Accordingly, the conditions at the bottom of the apparatus are controlled such that up to 70 wt.% Of the linear crude aldehyde in the liquid crude aldehyde product feedstock is removed and recovered in a stream of evaporated straight chain aldehyde discharged to the side of the apparatus. Likewise, said conditions are preferably controlled such that the resulting evaporated linear aldehyde may contain from 0% to 33% by weight of the organic heavy fractions of the crude liquid aldehyde mixture starting material. More preferably, the resulting purified straight-chain aldehyde contains less than 10% by weight of the organic heavy fractions present in the liquid crude aldehyde mixture starting material.

From the bottom of the distillation column 10, the remaining purified liquid aldehyde product is easily removed and recovered as a liquid stream containing 30-95% by weight of the straight aldehyde in the crude aldehyde starting material and the amount of organic heavy fractions present in the liquid aldehyde is less than 1% by weight of the total amount of aldehyde fed to the distillation column 10 and at least 67% by weight of the organic heavy fractions present in the liquid crude aldehyde mixture starting material, preferably at least 90% by weight.

The refining process of the present invention is truly unique in that it not only eliminates very significant energy savings by eliminating the conventional double-distillation described above, but also at least eliminates or significantly reduces the above-described conversion of aldehyde to organic heavy fractions by conventional distillation processes. while providing a stream of three different purified aldehyde products from a single distillation column.

It is, of course, essential that hydroformylated aldehyde products be used for a number of known and conventional purposes. Such aldehyde products are traditionally most preferred for the preparation of alcohols and other useful solvents.

The invention is further illustrated by the following non-limiting examples. In the remainder of the specification and in the claims, percentages, ratios, and ratios, unless otherwise indicated, parts by weight, percentages by weight, and percentages by weight are to be understood as being free metal.

• · · ·

Example 1

The following computational (calculated) simulation is performed to illustrate the process of the present invention.

As shown in the drawing, a crude mixture of n- and isobutyraldehyde containing 84 lbs / l and 0.24 isobutyraldehyde lighter and 0.4% n-butyraldehyde is fed as a theoretical plate at the bottom of a distillation column containing 105 theoretical plates. The light impurities, together with a small number of branched aldehydes, are removed at the top of the column 10, partially cooled in the cooler 15 and collected in the collecting vessel 17. A portion of the resulting liquid stream is returned to the column 10 (stream 7) as a reflux; 9.7 kg / hr material is removed from the system as 3 and 6 flow streams. On the theoretical plate 103 from the bottom of column 10, 952 kg / h of product (liquid stream 8) is discharged on the side of column 10. In theoretical plate 3 from the bottom of the apparatus, a stream of steam of 3266 kg / h was conducted on the side of column 10 as a high purity n-butyraldehyde product (stream 12). This steam stream passes through a small droplet separator (not shown) to remove the liquid entrapped by the steam stream. From the bottom of column 10, 4128 kg / hr of liquid stream was discharged as the second purified n-butyraldehyde product (stream 14). The bottom temperature of the 10 distillation columns is 99 ° C, at its wages • · · • · · ·

- the pressure at the top of 25 arrangements is 69,4 kPa. The isobutyraldehyde content of the upper side stream is 99.9%; 0.93% heavy fraction fraction of n-butyraldehyde stream 14 discharged to bottom of apparatus; the concentration of heavy fractions in the feed 2 and in the down stream 12 300: 1. The content of the heavy fractions in the stream 14 is substantially the same as that of the stream 2 of the stream 2, to which is added 0.1% of the aldehyde mixture of the same stream.

Example 2

From the actual operating data of an industrial system, the following will be described to illustrate the process of the present invention.

As shown in the drawing, a crude mixture of n- and isobutyraldehyde containing 0.072% lighter than 0.01% isobutyraldehyde and 0.4% n-butyraldehyde was fed at 9072 kg / h at the bottom of a theoretical plate 61 distillation column containing 105 theoretical plates. The light impurities, together with a small number of branched aldehydes, are removed at the top of the column 10, partially cooled in the cooler 15, and collected in the receptacle 17. A portion of the resulting fluid stream is recycled to reflux column 10 (stream 5); 90.7 kg / hr material is removed from the system as 3 and 6 flow streams. In the 103rd theoretical plate from the bottom of column 10, 987 kg / h of isobutyraldehyde product (liquid 8 stream) are discharged at the side of the column 10 · Theoretical plate 3 from the bottom of the apparatus at plate 10, 2268 kg / h of steam are passed as high purity n-butyraldehyde product (12 streams). This steam stream passes through a small droplet separator (not shown) to remove the liquid entrapped by the steam stream. From the bottom of column 10, 5727 kg / hr of liquid stream was discharged as the second purified n-butyraldehyde product (stream 14). The bottom temperature of the distillation column 10 is 105 ° C and the pressure at the top of the apparatus is 58.6 kPa. The isobutyraldehyde content of the upper side stream is 99.6%; a 0.7% heavy fraction content of the n-butyraldehyde stream 14 discharged to the bottom of the apparatus;

the concentration of heavy fractions in the feed stream 2 and the steam stream 12 downstream is 36: 1. The content of heavy fractions in material stream 14 is substantially the same as the content of heavy fraction in material stream 2, to which is added 0.04% of the aldehyde mixture content of the same stream.

Example 3

The following computational (calculated) simulation is performed to illustrate the process of the present invention.

As shown in the figure, a mixture of crude n- and isobutyraldehyde containing 2 lighter streams than 0.2% isobutyraldehyde and 2.6% n-butyraldehyde is fed at a rate of 8595 kg / h from the bottom of a distillation column containing 105 theoretical plates.

61. on a theoretical plate. The light impurities, together with a small number of branched aldehydes, are removed at the top of the column 10, partially cooled in the cooler 15, and collected in the receptacle 17. A portion of the resulting liquid stream is returned to the column 10 (stream 7) as a reflux; 108.8 kg / hr material is removed from the system as 3 and 6 flow streams. On the theoretical plate 103 from the bottom of column 10, 930 kg / h of product (liquid stream 8) is discharged on the side of column 10. In theoretical plate 3 from the bottom of the apparatus, a stream of steam of 3266 kg / h was conducted on the side of column 10 as a high purity n-butyraldehyde product (stream 12).

This steam stream passes through a small droplet separator (not shown) to remove the liquid entrapped by the steam stream. From the bottom of column 10, 4291 kg / h of liquid material stream was discharged as second purified n-butyraldehyde product (material stream 14). The bottom temperature of the distillation column 10 is 101 ° C and the pressure at the top of the apparatus is 69.4 kPa. The isobutyraldehyde content of the upper 8 side streams is 99.8%; the heavy fraction content of the n-butyraldehyde stream 14 discharged to the bottom of the apparatus was 6.1%; the concentration of heavy fractions in the feed stream 2 and the steam stream 12 downstream is 161: 1. The content of heavy fractions in material stream 14 is substantially the same as the content of heavy fraction in material stream 2, to which is added 0.45% of the aldehyde mixture content of the same stream.

Example 4

The following computational (calculated) simulation is performed to illustrate the process of the present invention.

As shown in the drawing, a mixture of 0.1%, lighter than branched pentanals and 0.3% of crude n- and branched pentanals containing 10.070 kg / h containing 105 theoretical plates is fed as 2 streams. 61 from the bottom of the distillation column. The light impurities, together with a small number of branched aldehydes, are removed at the top of the column 10, partially cooled in the cooler 15 and collected in the collecting vessel 17. A portion of the resulting fluid stream is recycled to reflux column 10 (stream 5); 90.7 kg / hr material is removed from the system as 3 and 6 blast streams. On the theoretical plate 103 from the bottom of column 10, 3039 kg / h of branched aldehyde (essentially 2-methylbutyraldehyde) product (liquid stream 8) are discharged on the side of column 10. On the theoretical plate 3 from the bottom of the apparatus, a stream of steam of 1950 kg / h was conducted on the side of column 10 as a high purity n-pentanal product (stream 12). This steam stream passes through a small droplet separator (not shown) to remove the liquid entrapped by the steam stream. From the bottom of column 10, 989 kg / hr of liquid stream was discharged as the second purified n-pentanal product (stream 14). The bottom temperature of the distillation column 10 is 129 ° C, the apparatus

the pressure at the top is 69.4 kPa. The branched aldehyde content of the upper side stream is 99.8%; 0.7% of the heavy fraction content of the n-pentanal material stream 14 discharged to the bottom of the apparatus; the ratio of heavy fraction concentration in feed stream 2 and steam stream 12 downstream is 4: 1. The content of the heavy fractions in the stream 14 is substantially the same as that of the stream 2 of the stream 2, to which is added 0.05% of the aldehyde mixture of the same stream.

Many modifications and variations of the process of the invention will be apparent to those skilled in the art, and such modifications and variations will, of course, fall within the scope of the application and the scope of the invention.

Claims (7)

Claims A process for refining a liquid crude aldehyde mixture product, wherein the crude product comprises 95-99.95% by weight of straight and / or branched aldehydes having from 4 to 5 carbon atoms, based on the total weight of the product, and comprising the remaining organic heavy fractions. passing the liquid crude aldehyde mixture product starting material into a distillation column (10) and distilling the normal boiling point of the straight chain aldehyde in the starting material at a temperature above 1-35 ° C (i) a stream of liquid aldehyde consisting essentially of purified branched aldehyde at or near the top of the distillation column (10); (ii) up to 70% by weight of straight chain aldehyde in the starting material and 33% by weight of organic heavy fractions in the starting material; (iii) less than 1% by weight of organic heavy fraction on the bottom of or near the bottom of the distillation column (10) fed to the distillation column (10) and at least a heavy fraction of starting material Purified liquid aldehyde containing 67% by weight was obtained. Process according to claim 1, characterized in that the distillation is carried out at a bottom temperature above 10 ° C to 35 ° C above the normal boiling point of the linear aldehyde. 3. A process according to claim 2 wherein the crude aldehyde mixture product is n-butanol and isobutanol. 4. The process of claim 2 wherein the crude aldehyde mixture product is n-pentanal and branched pentanal starting material. A process according to claim 1, wherein the distillation is carried out at a head pressure of 6,94 to 207 kPa. 6. The process according to claim 3, wherein the distillation is carried out at a head pressure of 6,94 to 103.5 kPa. Process according to claim 4, characterized in that the distillation is carried out at a head pressure of 6,94 to 103.5 kPa.